Electrochemical carbon nanotube filter and method

• US 9,827,517 B2
• Filed: 04/04/2012
• Issued: 11/28/2017
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Vecitis, Chad D., Van Fossen, Kirsten
• Primary Examiner(s): Friday, Steven A.
• Application Number:
  US13/439,073
• Publication Number:
  US 20120234694A1
• Time in Patent Office: 2,064 Days
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material
• CPC Class Codes: B01D 35/06 Filters making use of electricity or magnetism ultrafiltration, microfiltration B01D61/14; electrodialysis, electro-osmosis B01D61/42; devices comprising filters and magnetic separators B03C1/30
• CPC Class Codes: B01D 39/2055 Carbonaceous material solid sorbent compositions comprising free carbon B01J20/20
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C02F 1/4672 by electrooxydation

Abstract

A filtration apparatus and filtration method can be used to reduce at least one contaminant (e.g., organic molecules, ions and/or biological microorganisms) in an aqueous fluid. The filtration apparatuses and methods of the invention can separate at least one contaminant from an aqueous fluid and/or oxidize at least one contaminant. In operation, an aqueous fluid is flowed through a filtration apparatus comprising a porous carbon nanotube filter material at an applied voltage. In some embodiments, the filtration apparatus described herein can be used for dead-end filtration. In some embodiments, the filtration apparatus described herein can be used for cross-over filtration.

Claims

1. A filtration apparatus, comprising:

a housing forming a chamber having a plane, the chamber including an inlet for receiving an input fluid, a first outlet for releasing fluid, and a second outlet for releasing filtered fluid, wherein the inlet and the first outlet are disposed on a first side of the plane, and the second outlet is disposed on a second side of the plane;

a filter positioned along the plane between the inlet and the second outlet, the filter comprising at least one porous polymer layer disposed between a first porous carbon nanotube filter material and a second porous carbon nanotube filter material;

a first conducting connector positioned along the plane between the inlet and the carbon nanotube-based filter; and

a second conducting connector positioned along the plane between the carbon nanotube-based filter and the second outlet;

wherein the first and the second porous carbon nanotube filter material have an average pore size of at least about 0.5 nm; and

wherein the first and the second porous carbon nanotube filter material have a specific surface area of about 80 m²/g to about 120 m²/g.

2. The apparatus of claim 1, wherein the first conducting connector is in contact with a portion of the first porous carbon nanotube filter material.

3. The apparatus of claim 1, wherein the second conducting connector is in contact with a portion of the second porous carbon nanotube filter material.

4. The apparatus of claim 1, wherein at least one of the first conducting connector and the second conducting connector has a thickness of about 100 μ

m to about 150 μ

m.

5. The apparatus of claim 1, wherein the first conducting connector and the second conducting connector are electrically separated from each other to prevent a short circuit.

6. The apparatus of claim 5, wherein the first conducting connector and the second conducting connector each comprises at least one hole designed for a peg to align the first conducting connector and the second conducting connector with the filter.

7. The apparatus of claim 6, wherein a rim of the hole is coated with an electrically insulating layer.

8. The apparatus of claim 6, wherein the peg is an electrically-insulating peg.

9. The apparatus of claim 1, wherein at least one of the first conducting connector and the second conducting connector includes titanium.

10. The apparatus of claim 1, wherein a flux through the porous polymer layer is at least 70% of a flux through the first porous carbon nanotube filter material or the second porous carbon nanotube filter material.

11. The apparatus of claim 10, wherein the porous polymer layer has a pore size of about 0.01 μ

m to about 5 μ

m.

12. The filtration apparatus of claim 1, wherein the first and the second porous carbon nanotube filter materials comprise undoped carbon nanotubes, nitrogen-doped carbon nanotubes, boron-doped carbon nanotubes, fluorine-doped carbon nanotubes or any combinations thereof.

13. The filtration apparatus of claim 12, wherein the carbon nanotubes are multi-walled carbon nanotubes.

14. The filtration apparatus of claim 1, wherein the first conducting connector and the second conducting connector are connected to an electrical power source and produce an electric potential of 3 volts or less between the first porous carbon nanotube filter material and the first porous carbon nanotube filter material.